Connecting device for displaying units



FIG. 1 is a top perspective view of the design;

FIG. 2 is a top plan view of the design, the bottom plan view being identical;

FIG. 3 is a front view of the design, the rear view being identical; and,

FIG. 4 is a side view of the design, both side views being identical. 

The ornamental design for a connecting device for displaying units, as shown and described. 